Process of rendering calcium cyanamid non-dusting.



FRANK s. WASHIBURN, or NASHVILLE, TENNESSEE.

PROCESS OF RENDERING CALCIUM CYANAMID NON-DUSTING.

No Drawing.

To all whom it may concern Be it known that I, FRANK S. lVAsHBUnN, a citizen of the United States, residing at Nashville, in the county of Davidson and State of Tennessee, have invented certain new and useful Improvements in Processes of Rendering Calcium Cyanamid Non-Dusting; and I do hereby declare the following to be a full, clear, and exact description of the invention, such as will enable others skilled in the art to which it appertains to make and use the same.

This invention relates to a method of changing commercial calcium cyanamid from a fine dust into a granular condition, and has for its object to produce a product which while having all the present desirable properties of this compound, yet will, not have the objectionable qualities that are now met with in handling and using said compound.

To these ends the invent-ion consists in the novel steps constituting my process as Well as in the novel resulting product, all as will be more fully hereinafter disclosed and particularly pointed out in the claims.

In order that my invention may be fully understood, the present objections that are met with in the handling and use of commercial calcium cyanamid are stated as follows :-Commercial calcium cyanamid, or lime nitrogen as it is commonly called, when made contains among other things about 25% of free calcium hydrate Ca(OH) as well as some calcium oxid CaO, or caustic lime, and the physical condition of the mass is that of a very fine and almost impalpable powder. In use this powder, before it is sold to the farmers, is usually mixed with various materials generally consisting in part of phosphoric acid, in part of potash, and in part of nitrogenous matter. While carrying out this mixing process, it is found difficult to confine the very finely divided powder in ordinary mechanical mixers; and owing to its impalpable nature it is readily supported in the air and therefore fills the atmosphere with a penetrating dust which is exceedingly disagreeable to the workmen. It also enters the clothing and causes irritation to the skin. Again, owing to its great degree of fineness, a very large surface is exposed, and consequently it rapidly combines chemically with the free acid of the mixed phosphatic material, gives rise to high temperatures and Specification of Letters Patent.

Patented Jan. '7, 1913.

Application filed June 3, 1912. Serial No. 701,380.

causes, to a greater or less extent, the phosphoric acid to change from a soluble to an insoluble form. Further, largely due to the relatively excessive surface exposed, in its finely subdivided condition, cyanamid when stored, takes up moisture. both free and combined, as well as carbon dioxid from the atmosphere, which results in an increased weight. This is a disadvantage in that the compounder may not be certain,

under such circumstances, of the definite jectionable by reason of the physical condition of the product as a fine powder.

Various attempts have been made in the past to overcome the unfavorable effects of free lime in lime-nitrogen. But all these attempts were along the line of neutralizing the free lime to form a neutral and stable salt of it, and in hydrating the free lime to lime hydrate, which did not change the lime-nitrogen into a granular condition. By my invention now to be described, however, all of these diflicult-ies are overcome in a comparatively inexpensive and expeditious manner.

I form the commercial cyanamid or limenitrogen, into briquets preferably under a high pressure, and preferably with a small per cent. of water,'whereupon a heavy compact flinty mass results. These briquets are then crushed to particles or granules .of the required size, such for example, as will pass through a screen of eight meshes to the square inch, but notthrough a screen of fifteen meshes to the inch. The exposed surface area of the resulting granular product per unit of weight vbeing enormously less than that of the powdered product and the moisture present or the water added serving to slake the lime theabove disadvantages are found to practically disappear.

In some cases, I prefer in order to attain an improved result to first mix with the lime nitrogen a nitrogenous waste, or other binder; to then briquet it, and to then crush it. Instead of the foregoing provarying proportions of solids.

:2. Th 'calcium cyanamid non-dusting which concedure, however, I may subject the lime nitrogen to the action of carbon dioxid either before or after mixing it with a nitrogenous organic waste or binding material, and then briquet and crush it as before. I may further add any suitable oil either while or before adding the organic waste material.

A suitable organic waste material is found in the composition known as stick water, which is a by-product" of meat packing houses containing various ingredients of an 7 animal origin boiled down to a solution of Other suitable organic wastes are found in sugar beet refuse, steep-Water from starch manufacture, tannery waste, etc. I

The coarser particles from the crushers are returned and recrushed, While the undersized particles are returned to the briqueting machine.

It will be seen from the foregoing that the physical size of the granules of the cyanamid and therefore many of its chemical properties can be easily controlled to suit all the exacting conditions of use.

The solids rather than the Water of the organic waste seem to neutralize the free cal cium oxid present, and probably chemically combine also with some of the calcium in the calcium cyanamid CaCN' so that the resulting product produced by the steps above differs from the now well known commercial calcium cyanamid, or lime nitrogen, in that it is non-dusting; it contains very much less free caustic lime, or none at all; when compounded with phosphatic inaterials the mixture contains much less insoluble phosphoric acid than heretofore, or none at all; and when a binder is employed, it contains such binder which may also have a high fertilizer value in itself.

It is obvious that those skilled in the art may vary the steps above Without departing from the spirit of my invention, and therefore I do not wish to be limited to this disclosure except as may be required by the claims. I

What I claim is 1. The process of rendering commercial calcium cyanamid non-dusting which consists informing thesame into briquets, crushing-the briquets to. the desired fineness, and subjecting the crushed product to a screenin action to insure the resulting granules being of the required size, substantially as escribed.

process of rendering commercial sists in mixing a binder with the finel divided mass, forming the same into briguets, crushing the briquets to the desired neness, and subjecting the crushed product to a-screening action to insure the resulting granules being of the .required size,

substantially as described.

3. The process of rendering commercial calcium cyanamid non-dusting which consists in mixing'an organic binder having a fertilizer value tothe'finely divided mass,

' forming the same into briquets, crushing the briquets to the desired fineness, and sub.-

jecting the crushed product to a screening action. to insure the resulting granules being of the required size, substantially as described. 1 i

4. The process of rendering commercial calcium cyanamid non-dusting which consists in mixing stick water with the finely divided mass, forming "the same into briquets, crushing the briquets to the desired fineness, and subjecting the crushed product to a screening action to insure the resulting granules being .of the required size, substantially as described.

5. The process of rendering commercial calcium cyanamid non-dusting which consists in adding stick water to'the finely divided mass, passing carbon dioxid through the same, forming the gmixture into briquets, and crushin the-briquets to the required fineness,- su stantiall-y as described.

6.. The process of rendering commercial calcium cyanamid non-dusting which consists in adding stick water to the finely divided mass, passing carbon dioxid through the same, adding oil to the mass, forming the mixture into briquets, and crushing the briquets to the required fineness, substantially as described.

7. The herein described improved product consisting of a fertilizer comprislng a non-dusting commercial calcium cyanamid containing substantially no free caustic v lime, substantially no insoluble hosphoric acid, and the cyanamid mass being in the form of granules of a predetermined size,

anamid mass being in the form of granules of a predetermined size, substantially as described.

9. The herein described improved prod- .uct consisting of a non-dusting commercial calcium cyanamid containin a binder itself having a fertilizer value, an the mass being composed of anules of" a predetermined size, substantia' y as described.

11. The herein'described improved prod- .uct consisting of a non-dusting commercial calcium cyanamid containing a binder com- 18. The herein described improved prodposed of stick water, and the mass being not consisting of commercial calcium cyanoomposed of granules of a predetermined amid in the form of granules of a predetersize, substantially as described. mined size, substantially as described.

5 12. The herein described improved prod- In testimony whereof, I a'lfix my signa-- 15 not consisting of a non-dusting commercial ture, in presence of two Witnesses.- calcium cyanamid containing a binder com- FRANK S. WA'SHBURN. posed of stick Water and oil, and the mass Witnesses: being composed of granules of a predeter- E. J. PRANKE',

10 mined size, substantially as described. H. A. BLACK. 

